...a sound knowledge of history, including religious history, and also of social and economic subjects, is of great help in teaching the Cause to intelligent people... (rdc 26)
(11:1)

...we, the few who have caught the vision, should not waste our energies beating up and down the paths pursued by humanity, and which are not solving its ghastly present-day problems. We should concentrate on the Cause, because it is what is needed to cure the world...
(11:2)

If the Baha'is want to be really effective in teaching the Cause they need to be much better informed and able to discuss intelligently, intellectually, the present condition of the world and its problems... We Baha'is should, in other words, arm our minds with knowledge in order to better demonstrate to, especially, the educated classes, the truths enshrined in our Faith... (coc 313)
(11:3)

Just one mature soul, with spiritual understanding and a profound knowledge of the Faith, can set a whole country ablaze -- so great is the power of the Cause to work through a pure and selfless channel. (rdc 28)
(11:4)

Teaching is of course the head corner-stone of all Baha'i service, but successful teaching is dependent upon many factors, one of which is the development of a true Baha'i way of living and the fulfilment of responsibilities which we have incurred. (coc 317)
(11:5)

...rest ye assured in the confirmations of the Merciful and the assistances of the Most High; become ye sanctified above and purified from this world and the inhabitants thereof; suffer your intention to become for the good of all; cut your attachment to the earth and like unto the essence of the spirit become ye light and delicate. Then with a firm resolution, a pure heart, a rejoiced spirit, and an eloquent tongue, engage your time in the promulgation of the divine principles... (tdp 67)
(11:6)

...the believers of God must become self-sacrificing and like unto the candles of guidance become ignited... Should they show forth such a magnanimity, it is assured that they will obtain universal divine confirmations, the heavenly cohorts will reinforce them uninterruptedly, and a most great victory will be obtained... (tdp 27)
(11:7)

By the Lord of the Kingdom! If one arise to promote the Word of God with a pure heart, overflowing with the love of God and severed from the world, the Lord of Hosts will assist him with such a power as will penetrate the core of the existent beings. (tdp 348)
(11:8)

If thou wishest to guide the souls, it is incumbent on thee to be firm, to be good and to be imbued with praiseworthy attributes and divine qualities under all circumstances. Be a sign of love, a manifestation of mercy, a fountain of tenderness, kind-hearted, good to all and gentle to the servants of God, and especially to those who bear relation to thee, both men and women. Bear every ordeal that befalleth thee from the people and confront them not save with kindness, with great love and good wishes. (tb3 619)
(11:9)

First and foremost, one should use every possible means to purge one's heart and motives, otherwise, engaging in any form of enterprise would be futile. It is also essential to abstain from hypocrisy and blind imitation, inasmuch as their foul odour is soon detected by every man of understanding and wisdom. Moreover, the friends must observe the specific times for the remembrance of God, meditation, devotion and prayer, as it is highly unlikely, nay impossible, for any enterprise to prosper and develop when deprived of divine bestowals and confirmation. One can hardly imagine what a great influence genuine love, truthfulness and purity of motives exert on the souls of men. But these traits cannot be acquired by any believer unless he makes a daily effort to gain them...
(11:10)

It is primarily through the potency of noble deeds and character, rather than by the power of exposition and proofs, that the friends of God should demonstrate to the world that what has been promised by God is bound to happen, that it is already taking place and that the divine glad-tidings are clear, evident and complete... (letter 19 December 1923 by Shoghi Effendi to the Baha'is of the East)
(11:11)

Having . .. obtained a clear understanding of the true character of our mission, the methods to adopt, the course to pursue, and having attained sufficiently the individual regeneration -- the essential requisite of teaching -- let us arise to teach His Cause with righteousness, conviction, understanding and vigor. Let this be the paramount and most urgent duty of every Baha'i. Let us make it the dominating passion of our life. Let us scatter to the uttermost corners of the earth; sacrifice our personal interests, comforts, tastes and pleasures; mingle with the divers kindreds and peoples of the world; familiarize ourselves with their manners, traditions, thoughts and customs; arouse, stimulate and maintain universal interest in the Movement, and at the same time endeavor by all the means in our power, by concentrated and persistent attention, to enlist the unreserved allegiance and the active support of the more hopeful and receptive among our hearers. Let us too bear in mind the example which our beloved Master has clearly set before us. Wise and tactful in His approach, wakeful and attentive in His early intercourse, broad and liberal in all His public utterances, cautious and gradual in the unfolding of the essential verities of the Cause, passionate in His appeal yet sober in argument, confident in tone, unswerving in conviction, dignified in His manners -- such were the distinguishing features of our Beloved's noble presentation of the Cause of Baha'u'llah. (bad 69)
(11:12)

Every laborer in those fields, whether as traveling teacher or settler, should, I feel, make it his chief and constant concern to mix, in a friendly manner, with all sections of the population, irrespective of class, creed, nationality, or color, to familiarize himself with their ideas, tastes, and habits, to study the approach best suited to them, to concentrate, patiently and tactfully, on a few who have shown marked capacity and receptivity, and to endeavor, with extreme kindness, to implant such love, zeal, and devotion in their hearts as to enable them to become in turn self-sufficient and independent promoters of the Faith in their respective localities... (adj 65)
(11:13)

"...Say: O people of God! That which can insure the victory of Him Who is the Eternal Truth, His hosts and helpers on earth, have been set down in the sacred Books and Scriptures, and are as clear and manifest as the sun. These hosts are such righteous deeds, such conduct and character, as are acceptable in His sight. Whoso ariseth, in this Day, to aid Our Cause, and summoneth to his assistance the hosts of a praiseworthy character and upright conduct, the influence from such an action will, most certainly, be diffused throughout the whole world." (adj 20)
(11:14)

"...the believers of God must become self-sacrificing and like unto the candles of guidance become ignited... "Should they show forth such a magnanimity, it is assured that they will obtain universal divine confirmations, the heavenly cohorts will reinforce them uninterruptedly, and a most great victory will be obtained." (tdp 49)
(11:15)

"If the friends always waited until they were 'fully' qualified to do any particular task, the work of the Cause would be almost at a standstill! But the very act of striving to serve, however unworthy one may feel, attracts the blessings of God and enables one to become more fitted for the task.
(11:16)

"Today the need is so great on the part of humanity to hear of the Divine Message, that the believers must plunge into the work, wherever and however they can, heedless of their own shortcomings, but ever heedful of the crying need of their fellowmen to hear of the teachings in their darkest hour of travail." (letter 4 May 1942 on behalf S. Effendi)
(11:17)

"The Cause of God has room for all. It would, indeed, not be the Cause of God if it did not take in and welcome everyone -- poor and rich, educated and ignorant, the unknown and the prominent -- God surely wants them all, as He created them all." (letter 10 December 1942 on behalf S. Effendi)
(11:18)